Retake SAT senior year with good junior year score?

Do I need to retake my SAT my senior year even if I got a score I'm satisfied with? I am 16 and in 11th grade. I have 4.0 gpa and haven't taken SAT yet. I am great at taking tests so I am taking it Dec. 3rd and then again in May or June.

Also would it be possible for me to pass a Math 2 in June without taking trig this year? I haven't taken trig yet and am taking pre calc this year as well as AP stats.

No, you don't need to retake the SAT senior year if you get a score you're satisfied with in junior year.

As for the SAT Math 2 subject test, it's certainly possible to take it without having taken trignometry, especially if you cover some trig materials in your precalc class. We have an article with more detail about when to take Math 2 in this article.